Reverse rupture disk assembly for electrical transformer rapid depressurization and explosion prevention system

ABSTRACT

An electrical transformer system includes an electrical transformer and a depressurization system in fluid communication with an outlet of the electrical transformer. The depressurization system may include a rupture disk having a downwardly facing domed portion extending toward the outlet of the electrical transformer. The domed portion has an apex and a base with a retention portion surrounding the domed portion adjacent the base. A score line network extends circumferentially around the domed portion adjacent the base and spaced apart from the apex. The score line network includes a plurality of serrated score line segments and a plurality of hinge score line extending from the score line segments towards the apex of dome portion. The rupture disk may be interested into a housing assembly with a removable cover.

PRIORITY

The present application claims priority to U.S. Provisional ApplicationNo. 62/903,523, filed Sep. 20, 2019, the benefit of which is claimed andthe disclosure of which is incorporated herein by reference in itsentirety.

BACKGROUND

Electrical transformers are commonly found as components within a powergrid used for either “stepping up” or “stepping down” voltage of analternating current to allow for more efficient transportation ofelectrical power within the power grid. Transformers alter the voltageof the alternating current flowing through it by inductively couplingtwo conductors housed within the transformer. Specifically, both of theconductors include coils that are individually wound about a core (e.g.,a silicon steel core having high magnetic flux permeability), where eachcoil includes a specific number of turns or windings and the change involtage of the current flowing through the two inductively coupledconductors is proportional to the ratio of turns of the coil for eachconductor.

Due to the high amount of current flowing through the two conductors ofthe transformer significant heat is generated internally by thetransformer and thus, each conductor's coil is housed within a sealedchamber containing a coolant to prevent damaging critical components ofthe transformer, such as the insulation covering the individual windingsfor each conductor. For instance, transformers often include oil, suchas mineral oil, within the sealed chamber to provide cooling to theinductively coupled conductors. In this arrangement, oil may becirculated from the chamber and through a heat exchanger to cool theoil, so it may be recirculated back into the sealed chamber to furthercool the conductors. Because the oil used in cooling the conductors isoften flammable, an ignition source (i.e., a spark) within the sealedchamber may ignite the oil, causing the oil to rapidly heat and expandas it vaporizes, resulting in a rapid increase in the pressure of fluidwithin the chamber.

For this reason, some transformers include a pressure relief valve (PRV)coupled to the chamber and configured to open in the event of anoverpressurization of the chamber so as to reduce fluid pressure withinthe sealed chamber by releasing fluid from the chamber and to, forexample, the surrounding environment. For instance, PRVs often include aspring having a stiffness corresponding to the amount of absolutepressure at which the PRV is meant to actuate. However, a period of timeexists between the overpressurization event (i.e., spark and subsequentignition) and the complete actuation of the PRV, which is sometimesreferred to as the “response time” of the PRV.

More recently, rather than a pressure relief vale coupled to thetransformer as described above, a depressurization fluid circuit isutilized, in which a domed, segmented burst disk is configured to burstor rupture when exposed to a predetermined differential pressure acrossthe upstream and downstream faces of the disk. In such systems, thedomed burst disk has a domed circular shape which is convex on thedownstream or “dry” face of the disk and concave on the upstream or“wet” face of the disk. The dome is segmented (usually into sixequivalent segments) by score lines extending from the apex of the dometo the peripheral edge of the dome. At the base of the dome is acircular retention portion formed of a thin metal sheet, which retentionportion is clamped between two opposing circular flanges. As pressurewithin the transformer increases, pressurized fluid in the transformer,which may be in the form of liquid, gas or both, applies a force to theconcave face of the burst disk. Where the fluid pressure is greatenough, reaching a predetermined burst pressure, the dome will tearalong one or more of the score lines extending from the apex, therebyrupturing to allow relief of the pressure within the transformer.

During normal operations, fluid pressures within the transformerfluctuate below the burst pressure as the oil within the transformerheats and cools, the result being that the concave face of the burstdisk is constantly subject to fluctuating pressures. Moreover, it willbe appreciated that the burst disk oriented as described above is alwaysunder tension because fluid pressure in the transformer is alwaysapplying pressure to the concave face of the dome. As such, pressurefluctuations simply increase tension on the burst disk, and inparticular the score lines of the disk. Since the burst disk isconstantly in a state of tension, these pressure fluctuations can causethe score lines to rupture prematurely. Moreover, in the prior artutilizing a burst disk with score lines as described, pressure pulsesfrom pressure fluctuations are most likely to be initially mostconcentrated at the apex of the disk, thus further enhancing thelikelihood of early rupture of the burst disk system of the prior art.

BRIEF DESCRIPTION OF THE DRAWINGS

For a detailed description of exemplary embodiments, reference will nowbe made to the accompanying drawings in which:

FIG. 1A is a front elevation view of an electrical transformer system inaccordance with the teachings herein;

FIG. 1B is a perspective view of the depressurization system of FIG. 1A;

FIG. 2A is a side elevation view of one embodiment of a depressurizationsystem denoted by line A in FIG. 1A;

FIG. 2B is a side elevation view of another embodiment of adepressurization system denoted by line A in FIG. 1A;

FIG. 3A is an exploded side elevation view of an embodiment of a rupturedisk assembly in accordance with the teachings herein;

FIG. 3B is an exploded side elevation view of another embodiment of arupture disk assembly in accordance with the teachings herein;

FIG. 4A is a perspective view of a rupture disk housing assembly inaccordance with the teachings herein;

FIG. 4B is a side elevation view of the rupture disk housing assembly ofFIG. 3A;

FIG. 4C is a front elevation view of the rupture disk housing assemblyof FIG. 3A;

FIG. 5A is a perspective view of one embodiment of a rupture disk forincorporation into the rupture disk assembly in accordance with theteachings herein;

FIG. 5B is a perspective view of a ruptured rupture disk of FIG. 5A;

FIG. 6A is a cut-away side elevation view of a rupture disk assembly inaccordance with the teachings herein;

FIG. 6B is an exploded perspective view of a rupture disk assembly inaccordance with the teachings herein.

DETAILED DESCRIPTION

In the drawings and description that follow, like parts are typicallymarked throughout the specification and drawings with the same referencenumerals. The drawing figures are not necessarily to scale. Certainfeatures of the invention may be shown exaggerated in scale or insomewhat schematic form and some details of conventional elements maynot be shown in the interest of clarity and conciseness. The presentdisclosure is susceptible to embodiments of different forms. Specificembodiments are described in detail and are shown in the drawings, withthe understanding that the present disclosure is to be considered anexemplification of the principles of the disclosure and is not intendedto limit the disclosure to that illustrated and described herein. It isto be fully recognized that the different teachings of the embodimentsdiscussed below may be employed separately or in any suitablecombination to produce desired results.

Unless otherwise specified, in the following discussion and in theclaims, the terms “including” and “comprising” are used in an open-endedfashion, and thus should be interpreted to mean “including, but notlimited to”. Any use of any form of the terms “connect”, “engage”,“couple”, “attach”, or any other term describing an interaction betweenelements is not meant to limit the interaction to direct interactionbetween the elements and may also include indirect interaction betweenthe elements described. The term “fluid” may refer to a liquid or gasand is not solely related to any particular type of fluid such ashydrocarbons. The terms “pipe”, “conduit”, “line” or the like refers toany fluid transmission means. The various characteristics mentionedabove, as well as other features and characteristics described in moredetail below, will be readily apparent to those skilled in the art uponreading the following detailed description of the embodiments, and byreferring to the accompanying drawings.

Disclosed herein are embodiments of a depressurization system configuredfor use with an electrical transformer wherein the depressurizationsystem utilizes a domed rupture disk positioned so that the domedportion of the rupture disk extends towards the sealed chamber of atransformer. In one or more embodiments, the burst disk is provided withscore lines limited to the outer edge of the burst disk, with the domeof the burst disk being free of score lines. Embodiments of thedepressurization system may include a rupture disk housing assemblydeployed in-line along duct piping, where the housing assembly includesa removable cover and is disposed to receive a rupture disk cartridgewith a rupture disk oriented as described.

Referring initially to FIGS. 1A-1B, an electrical transformer system 10is shown that includes an electrical transformer 20 having an embodimentof a depressurization system 100 coupled thereto. The transformer 20includes a sealed chamber 22 having a generally upwardly facing surface23, electrical cables 24 and depressurization system 100. Sealed chamber22 includes a magnetic core (not shown) and electrical conductors (notshown) disposed in a coolant (not shown) as is generally, understood inthe art. In the illustrated embodiment of transformer 20, the coolantcontained within chamber 22 is mineral oil. However, in otherembodiments chamber 22 may include other forms of coolant. In someembodiments, chamber 22 contains more than 1,000 gallons of coolant. Itwill be appreciated that depressurization system 100 may be utilizedwith any transformer and the above described electrical transformer 20is for illustrative purposes only.

During operation, a high amount of alternating current flows throughelectrical cables 24 to the conductors housed within chamber 22,generating and transferring heat to the coolant disposed therein. Sealedchamber 22 also includes a manhole 26, which includes an opening (notshown) that is configured to provide for fluid communication betweenchamber 22 and depressurization system 100. Thus, fluid pressurecontained within chamber 22 may be communicated to depressurizationsystem 100 via manhole 26. In one or more embodiments, manhole 26 isprovided in upwardly facing surface 21. During the operation oftransformer 20, an ignition event, such as a spark, may take placewithin chamber 22, which may result in the combustion of at least aportion of the coolant within chamber 22, rapidly elevating the fluidpressure within chamber 22 and communicated to depressurization system100.

Referring now to FIGS. 2A-2B, embodiments of a portion ofdepressurization system 100 of FIGS. 1A and 1B are shown in more detailas attached to transformer 20, and in particular, the rupture diskassembly 200 of depressurization system 100. In FIG. 2A, a rupture diskassembly 200 is shown coupled in-line along a flow path defined by afirst pipe section 202 and a second pipe section 204. In one or moreembodiments, as illustrated, first pipe section 202 may be a riser andsecond pipe section 204 may be an elbow or another riser. In one or moreembodiments, first pipe section 202 is substantially straight or linearto minimize flow impedance along the flow path between first pipesection 202 and chamber 22. In this regard, first pipe section 22 may berelatively short so that rupture disk assembly 200 is in close proximityto chamber 22. For example, pipe section 202 may be linear and ofapproximately five (5) feet or less, ensuring that rupture disk assembly200 is in close proximity to chamber 22. In this regard, linear pipesection 202 may extend from upwardly facing surface 23 of chamber 22such that rupture disk assembly 200 is in close proximity to chamber 22.In one or more embodiments, an additional valve 210 may be providedalong first pipe section 202 between transformer 20 and depressurizationsystem 100. Although not limited to a particular type of valve, in theillustrated embodiment, valve 210 is shown as a gate valve, moreparticularly a knife gate valve, which, it will be appreciated, can beclosed in order to isolate depressurization system 100 from fluid flowalong first pipe section 202, such as would be desired when performingmaintenance on depressurization system 100.

In FIG. 2A, rupture disk assembly 200 includes a rupture disk cartridgeassembly 230 bolted in-line between a first support fitting 207extending from first pipe section 202 and a second support fitting 209extending from second pipe section 204, One or both support fittings207, 209 may be integrally formed with their corresponding pipe section202, 204, respectively, or separate fittings sized and disposed toengage rupture disk cartridge assembly 230. In this regard, firstsupport fitting 207 includes a flange 207′ and second support fitting209 includes a flange 209′. Disk cartridge assembly 230 is shown ashaving a lower disk support plate 235 and an upper disk support plate250 which are joined together between flanges 207′, 209′ and secured byfasteners 221 extending through flanges 207′, 209′ so as to sandwichlower and upper disk support plates 235, 250 therebetween.

In FIG. 2B, rupture disk assembly 200 includes a rupture disk housingassembly 201 bolted in-line between a first support fitting 207extending from first pipe section 202 and a second support fitting 209extending from second pipe section 204. One or both support fittings207, 209 may be integrally formed with the housing assembly 201 (seeFIG. 4), or separate fittings sized and disposed to engage housingassembly 201. Housing assembly 201 includes a removable cover 214releasably secured by fasteners 232 to allow a rupture disk cartridgeassembly 230 (see FIG. 2A) to be inserted therein.

Turning more specifically to FIG. 3A, rupture disk cartridge assembly230 of depressurization system 100 (see FIGS. 1A and 1B) is shown inmore detail. In the illustrated embodiment, disk cartridge assembly 230includes a rupture disk 240 having a downwardly facing domed portion 242which is spherical in shape and which has a concave side or surface 246,which is a downstream side, and convex side or surface 248, which is anupstream side. For purposes of orientation and illustration, an arrow Fis shown to illustrate fluid pressure applied to rupture disk 240 in adeployed orientation, and more specifically, fluid pressure F applied tothe convex side 246. Domed portion 242 is characterized by an apex 243and a base 247. Rupture disk 240 further include a retention portion 244surrounding the domed portion 242 adjacent the base 247 of domed portion242. Each of domed portion 242 and retention portion 244 may have acircular shape about axis 223. As used herein, “downwardly” facing meansthat the domed portion extends in a direction back along the flow pathtowards the electrical transformer 20 and sealed chamber 22, such thatthe convex side 248 of the rupture disk is in fluid communication withthe sealed chamber 22, regardless of the particular orientation ofrupture disk 240. Moreover, in one or more embodiments, rupture disk 240is in close proximity to sealed chamber 22 to minimize the length of theflow path between sealed chamber 22 and rupture disk 240. Similarly,first pipe section 202 is preferably a linear pipe section, again tominimize impedances in the flow path between the sealed chamber 22 andrupture disk 240.

Rupture disk cartridge assembly 230 further includes a lower disksupport plate 235 and a upper disk support plate 250. Each support plate235, 250 has a bore 234 a, 234 b, respectively, formed therein alongcartridge axis 223 of rupture disk cartridge assembly 230. One or bothsupport plates 235, 250 may be a circular ring. Rupture disk 240 issecured between the lower and upper support plates 235, 250,respectively and oriented so that domed portion 242 extends downwardinto bore 234 a of lower or lower disk support plate 235. In particular,retention portion 244 of rupture disk 240 is clamped between lowersupport plate 235 and upper support plate 250 to secure rupture disk240. In some embodiments, lower disk support plate 235 is sufficientlyelongated or tubular in shape with a height H1 to receive and protectrupture disk 240 extending therein. In particular, in one or moreembodiments, height H1 of lower disk support plate 235 is selected to begreater than the height D1 of domed portion 242 of rupture disk 240. Inone or more embodiments, upper disk support plate 250 may be a circularring and have a height H2, which may be less than the height H1 of lowerdisk support plate 235. In other embodiments, height H2 of upper supportplate 250 may be equal to or greater than the height H1 of lower disksupport plate 235. In some embodiments, lower disk support plate 235 mayhave a recess 231 disposed in surface 237 thereof that complements aperimeter shape 245 of retention portion 244 for aligning rupture disk240 about axis 223. In any event, in some embodiments, lower disksupport plate 235 attaches to upper disk support plate 250 so as toclasp retention portion 244 therebetween, while in other embodiments,rupture disk cartridge assembly 230 may be simply clamped betweenadjacent flanges 207′, 209′, securing lower disk support plate 235 andupper disk support plate 250, and thus, rupture disk 240, therebetween,such as is shown in FIG. 2A.

With reference to FIG. 3B, another embodiment of rupture disk cartridgeassembly 230 is illustrated, where rupture disk housing 230 as shown inFIG. 3B is particularly well suited for insertion into rupture diskhousing assembly 201 generally depicted in FIG. 2B. As described above,disk cartridge assembly 230 includes a rupture disk 240 which is securedbetween the lower and upper disk support plates 235, 250, respectivelyand oriented so that domed portion 242 extends downward into bore 234 aof first or lower disk support plate 235. In embodiments where rupturedisk cartridge assembly 230 is to be inserted into a rupture diskhousing assembly 201, rupture disk cartridge assembly 230 may furtherinclude a base 239 supporting first or lower disk support plate 235. Inone or more embodiments, base 239 and lower support plate 235 may beintegrally formed, while in other embodiments, lower support plate 235may be separate from base 239 but supported by base 239.

With reference to FIGS. 4A-4C and on-going reference to FIGS. 2B and 3B,housing assembly 201 generally includes a container 212 to which aremovable cover 214 is secured. Container 212 includes an opening 213enclosed by removable cover 214. Opening 213 has a height 213 h and awidth 213 w and extends into an internal cavity 225 formed withincontainer 212. Housing assembly 201 further includes a first or lowerflange 216, and a second or upper flange 218. In one or moreembodiments, first flange 216 is disposed for attachment to first pipesection 202 (see FIG. 2B) and second flange 218 is disposed forattachment to second pipe section 204 (see FIG. 2B). A through bore 215is formed to extend between first flange 216 and second flange 218 alongaxis 211 and intersects cavity 225 for communicating fluid flow betweenfirst pipe section 202 and second pipe section 204. In the illustratedembodiment, first flange 216 connects to a first surface 212 d ofcontainer 212 via first housing riser 217 and second flange 218 connectsto a second surface 212 e of container 212 via second housing riser 219.In one or more embodiments, housing assembly 201 has a low profileselected to correspond generally with the approximate height DH1 of arupture disk 240 to be inserted into container 212. Thus, container 212,and specifically, internal cavity 225, is sized in shape and dimensionto receive a cartridge disk assembly 230 as described in more detailbelow.

It will be appreciated that when disk cartridge assembly 230 is seatedin disk housing assembly 201 as described herein, cartridge axis 223 andhousing axis 211 substantially align so that bore 215 of housingassembly 201 and bores 234 a, 234 b of disk cartridge assembly 230 arelikewise aligned as described herein. In one or more embodiments, lowerdisk support plate 235 may include splines 236 along one or both sides235 a thereof for engagement with complementing grooves (not shown) oninternal sidewalls of container 212 for leveling rupture disk cartridgeassembly 230 during insertion into rupture disk housing assembly 201.However, it will be appreciated that other structures may be used tofacilitate insertion of lower disk support plate 235 and/or diskcartridge assembly 230 into container 212.

In one or more embodiments, as illustrated, removable cover 214 may beattached to lower disk support plate 235, while in other embodiments,removable cover 214 may be separate from lower disk support plate 235.In the illustrated embodiment, fasteners 232 may be utilized to secureremovable cover 214 to container 212. In one or more embodiments,fasteners 232 may be housing weldments attached to the outside surface238 of container 212 about opening 213 to secure rupture disk cartridgeassembly 230 within housing assembly 201 by extending over removablecover 214 preventing removal thereof. In any event, removable cover 214functions to enclose opening 213 of container 212 and prevent removal ofdisk cartridge assembly 230 therefrom. In the illustrated embodiment,four fasteners 232 are shown. However, it will be appreciated that anynumber of housing fasteners 232 may be used. Moreover, while housingweldments are illustrated, it will be appreciated that fasteners 232 mayinclude, without limitation, pins, bolts, screws, clamps or otherdevices.

As described above, in one or more embodiments, container 212 has alow-profile shape with a height to width ratio substantially the same asthe height to width ratio (213 h:213 w) of opening 213 where the width213 w is greater than the height 213 h. In some embodiments, the width213 w is greater than twice the height 213 h, while in otherembodiments, the width 213 w is equal to or greater than four times theheight 213 h. In one or more embodiments, container 212 has a front side212 a in which opening 213 is formed, an opposing back side 212 b withside walls 212 c extending between front side 212 a and back side 212 b.In one or more embodiments, front side 212 a is substantially flat andback side 212 b is semicircular. In one or more embodiments, back side212 b is semicircular around housing axis 211.

Referring back to FIGS. 1A and 1B, in one or more embodiments,depressurization system 100 may include a substantially horizontal,elongated pipe 222 coupled to second pipe section 204 (see FIGS. 2A and2B). Elongated pipe 222 may function as an expansion reservoir forsealed chamber 22 when an ignition event occurs that results in ruptureof rupture disk 240 (see FIGS. 3 and 4), allowing liquid from sealedchamber 22 to temporarily flow into elongated pipe 222 via rupture diskassembly 200. In some embodiments, while elongated pipe 222 issubstantially horizontal, it may have a slight incline from the horizonso that any liquid that temporarily expands into elongated pipe 222 willthereafter drain back into sealed chamber 22. In one or moreembodiments, the incline is between 1 degree and 15 degrees with thehorizontal.

As will be appreciated, accompanying any liquid that might flow intoelongated pipe 222 may be ignition gasses. Thus, a flame suppressor 220may be disposed at the end of elongated pipe 222. In one or moreembodiments, flame suppressor 220 may be aligned with pipe 222 and eachis oriented substantially horizontally so that an outlet therefrom facessideways. In other embodiments, flame suppressor 220 may have adifferent orientation, such as a vertical orientation. The disclosure isnot limited to a particular orientation of flame suppressor 220.

In the above described embodiments, pipe 222 is selected to besufficiently long to temporarily receive oil (not shown) fromtransformer 20 during an overpressurization event. As stated, in someembodiments, pipe 222 may be constructed on a slight angle between thetwo ends of pipe 222 with the lower end coupled to second pipe section204 so as to be inclined toward housing assembly 201 to allow oil todrain back into transformer 20 after the overpressurization event. Inone or more embodiments, transformer 20 is in a building, or otherstructure, and pipe 222 passes to an outside of the building, or otherstructure, before connecting to flame suppressor 220. In one or moreembodiments, electrical transformer system 10 includes an oil collectiontank (not shown) connected to pipe 222 at a T-junction allowing oil tocollect via gravity into the oil collection tank while gas is routed toflame suppressor 220. In the illustrated embodiment, burning gases mayalso travel along elongated pipe 222 and be released from the end ofelongated pipe 222 into flame suppressor 220. Flame suppressor 220 isnot limited to a particular type but may be any device that functions tosuppress flames that may accompany the release of gases from elongatedpipe 222.

Although in some embodiments, downwardly facing domed rupture disk 240is not limited to a particular type, FIGS. 5A and 5B illustrate a domedrupture disk 240 that is particularly suited to the downwardly facingorientation contemplated by the disclosure. Specifically, in FIGS. 5Aand 5B, a score line network 249 is formed along the base 247 of domedportion 242 and spaced apart from apex 243 so that apex 243 is free ofany score lines. In particular, the score line network 249 is formed ofone or more score line segments 252 extending circumferentially aboutthe base 247. In some embodiments, a plurality of spaced apart scoreline segments 252 may be provided, as shown in FIG. 5A. Although thescore line segments 252 are not limited to a particular shape, in one ormore embodiments, the score line segments 252 are serrated. In one ormore embodiments, a plurality of serrated score line segments 252 areprovided with a score line hinge 254 extending from each score linesegment 252 towards the apex 243 of dome portion 242. In one or moreembodiments, each score line segment 252 includes a score line hinge 254at each end of the score line segment 252. In one or more embodiments,score line hinges 254 may be spaced apart from one another at the endsof adjacent serrated score line segments 252. When sufficient fluidpressure is placed on the convex side 248 of domed rupture disk 240,domed rupture disk 240 will rupture and tear along at least a portion ofthe score line network 249 formed along the base 247 of domed portion242, pushing domed portion 242 into bore 234 b. Thus, score line hinges254 allow rupture disk 240 to fold back on itself in the direction ofthe flow arrow F (see FIG. 5B), so as not to impede flow as would priorart rupture disks with tear lines formed in the domed portion of therupture disk. Moreover, as the tear progresses along serrated score linesegments 252 upon a rupture, the score line hinges 254 function tointerrupt progression of the tear as the tear force on rupture disk 240diminishes.

With reference to FIGS. 6A and 6B, disk cartridge assembly 30 isillustrated with an embodiment of the rupture disk 240 described in FIG.5A. Thus, as shown, rupture disk 240 is disposed between a lower disksupport plate 235 and an upper disk support plate 250 so that domedportion 242 of rupture disk 240 extends into bore 234 a of lower disksupport plate 235. Upper plate 250 abuts lower disk support plate 235 toengage retention portion 244 of rupture disk 240. In this regard,retention portion 244 may seat in a recess 231 formed in the uppersurface 237 of lower disk support plate 235. As shown, score linenetwork 249 is formed in domed portion 242 so as to be spaced apart fromapex 243 such that domed portion 242 of rupture disk 240 is free ofscore line network 249 at apex 243, but rather, score line network 249only extends circumferentially along the base 247 of domed portion 242.Score line network 249 includes one or more serrated score line segments252 with score line hinges 254 extending from the score line segments252 towards the apex 243 of dome portion 242.

Embodiments have been described in terms of rapidly relieving fluidpressure within a main fluid filled tank of electrical transformersystem 10, so as to reduce the risk of overpressurization. However; itwill be appreciated that embodiments can be used for other components ofelectrical transformer system 10, including without limitation bushingturrets, on load tap changers, and oil filled cable boxes.

Thus, a depressurization system for an electrical transformer has beendescribed. Embodiments of the depressurization system may generallyinclude a rupture disk housing assembly having a container with anopening, a first flange attached to the container, a second flangeattached to the container; and a rupture disk cartridge having a lowerdisk support plate with a bore formed therein; a upper disk supportplate with a bore formed therein; a rupture disk having a downwardlyfacing domed portion with a concave side and convex side; the domedportion characterized by an apex and a base, the rupture disk includinga retention portion surrounding the domed portion adjacent the base,wherein the rupture disk clamped between the lower disk support plateand the upper disk support plate so that the domed portion of therupture disk extends into the bore of the lower disk support plate;wherein the rupture disk cartridge is disposed within the container ofthe rupture disk housing. Other embodiments of the depressurizationsystem may include a rupture disk housing assembly having a containerwith an opening, a first flange attached to the container, a secondflange attached to the container; a removable cover enclosing theopening; and a rupture disk cartridge having a lower disk support platewith a bore formed therein; a upper disk support plate having a boreformed therein; a rupture disk having a downwardly facing domed portionwith a concave side and convex side, the domed portion characterized byan apex and a base, the rupture disk including a retention portionsurrounding the domed portion adjacent the base, with a score linenetwork extending circumferentially around the domed portion of rupturedisk adjacent the base and spaced apart from the apex, the score linenetwork having a plurality of score line segments, wherein the rupturedisk clamped between the lower disk support plate and the upper disksupport plate so that the domed portion of the rupture disk extends intothe bore of the lower disk support plate, wherein the rupture diskcartridge is disposed within the container of the rupture disk housing.Relatedly, embodiments of transformer system have been described and mayinclude an electrical transformer having a chamber in which a magneticcore and electrical conductors are disposed in a coolant, the chamberhaving an outlet defined therein; and a depressurization system in fluidcommunication with the outlet of the electrical transformer, thedepressurization system having a first pipe section extending from theoutlet so as to form a flowpath therebetween; a second pipe section influid communication with the first pipe section; and a rupture diskhaving a downwardly facing domed portion with a concave side and convexside, the domed portion characterized by an apex and a base, the rupturedisk including a retention portion surrounding the domed portionadjacent the base, wherein the rupture disk is positioned between thefirst pipe section and the second pipe section so that the domed portionof the rupture disk extends toward the first pipe section and electricaltransformer outlet so that the convex side of the rupture disk is influid communication with the flowpath between the first pipe section andthe chamber. Other embodiments of a transformer system may include anelectrical transformer having a chamber in which a magnetic core andelectrical conductors are disposed in a coolant, the chamber having anoutlet defined therein; and a depressurization system in fluidcommunication with the outlet of the electrical transformer, thedepressurization system having a first pipe section extending from theoutlet; a second pipe section in fluid communication with the first pipesection; and a rupture disk having a downwardly facing domed portionwith a concave side and convex side, the domed portion characterized byan apex and a base, the rupture disk including a retention portionsurrounding the domed portion adjacent the base, with a score linenetwork extending circumferentially around the domed portion of rupturedisk adjacent the base and spaced apart from the apex, the score linenetwork having a plurality of score line segments, wherein the rupturedisk clamped between the lower disk support plate and the upper disksupport plate so that the domed portion of the rupture disk extends intothe bore of the lower disk support plate, wherein the rupture disk ispositioned between the first pipe section and the second pipe section sothat the domed portion of the rupture disk extends toward the first pipesection and electrical transformer outlet.

For any one of the foregoing embodiments, the following elements may becombined alone or in combination with other elements:

-   -   The removable cover forms part of the rupture disk cartridge.    -   The removable cover is attached to the lower disk support plate.    -   The first pipe section is linear.    -   The first pipe section is approximately five feet or less in        length.    -   valve positioned between the rupture disk and the first pipe        section.    -   First linear pipe section extends from an upwardly facing        surface of the chamber.    -   The rupture disk assembly is in close proximity to an upwardly        facing surface of the chamber.    -   The rupture disk cartridge is pre-assembled outside the rupture        disk housing assembly.    -   The opening has a first height and a first width, wherein the        first height is at least equal to a height of the rupture disk        cartridge, wherein the first width is at least equal to a        diameter of the rupture disk cartridge.    -   The rupture disk comprises a domed portion and a retention        portion.    -   The lower disk support plate and the upper disk support plate        form metal to metal seals with the rupture disk retention        portion.    -   The transformer system of claim 8, wherein the first flange        connects to a first pipe section upstream of the        depressurization system and the second flange connects to a        second pipe section downstream of the depressurization system,        wherein the rupture disk cartridge is removable from the rupture        disk housing assembly without disconnecting either of the first        flange from the first pipe section or the second flange from the        second pipe section.    -   The removable cover forms part of the rupture disk cartridge.    -   A valve configured to block fluid communication between the        electrical transformer and the depressurization system.    -   A flame suppressor disposed downstream of the depressurization        system    -   The flame suppressor is oriented substantially horizontally.    -   The electrical transformer and the depressurization system are        disposed inside a structure, wherein the flame suppressor is        disposed outside the structure.    -   The lower disk support plate comprises a base and the upper disk        support plate comprises a circular ring.    -   The upper disk support plate is a ring disposed about an axis        with a bore formed through the ring.    -   The lower disk support plate is a ring disposed about an axis        with a bore formed through the ring.    -   Each disk support plate includes a bore formed therein.    -   The container is low profile with a container width that is at        least twice a height of the container.    -   The rupture disk is formed about an axis and comprises an upward        facing domed portion which is spherical in shape about the axis        and a substantially flat retention portion surrounding the domed        portion.    -   The upper disk support plate engages the rupture disk so that        the domed portion extends into a bore formed through the upper        disk support plate.    -   The retention portion is clasped between the lower disk support        plate and the upper disk support plate so that the axis of the        rupture disk aligns with the axis of each bore.    -   An internal cavity formed within the container.    -   A through bore formed through housing about a housing axis.    -   The container is low profile.    -   The container has a front side in which the opening is formed,        an opposing back side and side walls extending between front        side and back side,    -   The front side is substantially flat and the back side is        semicircular.    -   The cartridge base has a front side that is substantially flat        and an opposing back side that is semicircular in shape.    -   A substantially horizontal, elongated expansion pipe extending        between a first end and a second end with the first end in fluid        communication with the rupture disk housing.    -   A substantially horizontal flame suppressor attached to        elongated expansion pipe at the second end.    -   At least a portion of elongated expansion pipe between the two        ends forms an angle with the horizontal that is greater than        zero and less than 15 degrees.    -   A substantially vertical flame suppressor attached to elongated        expansion pipe at the second end,    -   A removable cover enclosing the opening.    -   The removable cover is attached to the lower disk support plate.    -   The rupture disk further comprises a score line network        extending circumferentially around the domed portion of rupture        disk adjacent the base and spaced apart from the apex.    -   The score line network comprises one or more serrated score        segments.    -   The score line network further comprises one or more hinge score        lines extending from the score line segments towards the apex of        dome portion.    -   The lower disk support plate and the upper disk support plate        form metal to metal seals with the rupture disk retention        portion.    -   The score line network further comprises a plurality of hinge        score line extending from the score line segments towards the        apex of dome portion    -   A base supporting lower support plate, wherein the removable        cover is attached to the base.    -   A rupture disk housing assembly having a container with an        opening therein to define a cavity, a first flange attached to        the container, a second flange attached to the container with a        through bore extending between the first flange and the second        flange and intersecting the cavity; and a removable cover        enclosing the opening, wherein the first flange connects to a        first pipe section upstream of the depressurization system and        the second flange connects to a second pipe section downstream        of the depressurization system, wherein the rupture disk is        removable from the rupture disk housing assembly, without        disconnecting either of the first flange from the first pipe        section or the second flange from the second pipe section.    -   A valve disposed between the electrical transformer and the        depressurization system.    -   An elongated, substantially horizontal pipe having a first end        attached to the second pipe section and a second end to which a        flame suppressor is attached.    -   The flame suppressor is oriented substantially horizontally.    -   Each score line segment includes two spaced apart hinge score    -   Hinge score lines may be spaced apart from one another at the        ends of adjacent score line segments.    -   The score line network has a plurality of score line segments.    -   The score line segments are serrated.

Thus, it is seen that the apparatus of the present invention readilyachieves the ends and advantages mentioned as well as those inherenttherein. While certain preferred embodiments of the present inventionhave been illustrated for the purposes of this disclosure, numerouschanges in the arrangement and construction of parts may be made bythose skilled in the art, which changes are encompassed within the scopeand spirit of the present invention as defined by the appended claims.

The invention claimed is:
 1. A depressurization system for an electricaltransformer, the depressurization system comprising: a rupture diskhousing assembly having a container with an opening therein to define acavity, a first flange attached to the container, a second flangeattached to the container with a through bore extending between thefirst flange and the second flange and intersecting the cavity; and aremovable cover enclosing the opening, wherein the first flange isconnectable to a first pipe section upstream of the depressurizationsystem and the second flange is connectable to a second pipe sectiondownstream of the depressurization system; a rupture disk cartridgecomprising a lower disk support plate having a bore formed therein; anupper disk support plate having a bore formed therein; a rupture diskhaving a domed portion with a concave side and convex side, the domedportion characterized by an apex and a base, the rupture disk includinga retention portion surrounding the domed portion adjacent the base,wherein the rupture disk clamped between the lower disk support plateand the upper disk support plate so that the domed portion of therupture disk extends into the bore of a disk support plate; wherein therupture disk cartridge is disposed within the container of the rupturedisk housing and wherein the rupture disk is removable from the rupturedisk housing assembly without disconnecting either of the first flangefrom the first pipe section or the second flange from the second pipesection.
 2. The depressurization system of claim 1, wherein theremovable cover is attached to the lower disk support plate.
 3. Thedepressurization system of claim 1, wherein the rupture disk furthercomprises a score line network extending circumferentially around thedomed portion of rupture disk adjacent the base and spaced apart fromthe apex.
 4. The depressurization system of claim 3, wherein the scoreline network comprises one or more serrated score line segments.
 5. Thedepressurization system of claim 4, wherein the score line networkfurther comprises one or more hinge score lines extending from the scoreline segments towards the apex of dome portion.
 6. The depressurizationsystem of claim 1, wherein the lower disk support plate and the upperdisk support plate form metal to metal seals with the rupture diskretention portion.
 7. A depressurization system for an electricaltransformer, the depressurization system comprising: a rupture diskhousing assembly having a container with an opening therein to define acavity, a first flange attached to the container, a second flangeattached to the container with a through bore extending between thefirst flange and the second flange and intersecting the cavity, whereinthe first flange is connectable to a first pipe section upstream of thedepressurization system and the second flange is connectable to a secondpipe section downstream of the depressurization system; a removablecover enclosing the opening; and a rupture disk cartridge comprising: alower disk support plate having a bore formed therein; an upper disksupport plate having a bore formed therein; a rupture disk having adomed portion with a concave side and convex side, the domed portioncharacterized by an apex and a base, the rupture disk including aretention portion surrounding the domed portion adjacent the base, witha score line network extending circumferentially around the domedportion of rupture disk adjacent the base and spaced apart from theapex, the score line network having a plurality of serrated score linesegments, wherein the rupture disk clamped between the lower disksupport plate and the upper disk support plate so that the domed portionof the rupture disk extends into the bore of a disk support plate;wherein the rupture disk cartridge is disposed within the container ofthe rupture disk housing and wherein the rupture disk cartridge isremovable from the rupture disk housing assembly without disconnectingeither of the first flange from the first pipe section or the secondflange from the second pipe section.
 8. The depressurization system ofclaim 7, wherein score line network further comprises a plurality ofhinge score line extending from the score line segments towards the apexof dome portion.
 9. The depressurization system of claim 7, wherein theremovable cover is attached to the lower disk support plate.
 10. Thedepressurization system of claim 7, further comprising a base supportinglower support plate, wherein the removable cover is attached to thebase.
 11. A transformer system comprising: an electrical transformerhaving a chamber in which a magnetic core and electrical conductors aredisposed in a coolant, the chamber having an outlet defined therein; adepressurization system in fluid communication with the outlet of theelectrical transformer, the depressurization system comprising: a firstpipe section extending from the outlet so as to form a flowpaththerebetween; a second pipe section in fluid communication with thefirst pipe section; a rupture disk having a domed portion with a concaveside and convex side, the domed portion characterized by an apex and abase, the rupture disk including a retention portion surrounding thedomed portion adjacent the base; a rupture disk housing assembly havinga container with an opening therein to define a cavity, a first flangeattached to the container, a second flange attached to the containerwith a through bore extending between the first flange and the secondflange and intersecting the cavity; and a removable cover enclosing theopening of the rupture disk housing, wherein the first flange connectsto the first pipe section upstream of the depressurization system andthe second flange connects to the second pipe section downstream of thedepressurization system, wherein the rupture disk is removable from therupture disk housing assembly without disconnecting either of the firstflange from the first pipe section or the second flange from the secondpipe section.
 12. The transformer system of claim 11 further comprisinga valve disposed between the electrical transformer and thedepressurization system.
 13. The transformer system of claim 11 furthercomprising an elongated, substantially horizontal pipe having a firstend attached to the second pipe section and a second end to which aflame suppressor is attached.
 14. The transformer system of claim 13,wherein the flame suppressor is oriented substantially horizontally. 15.The transformer system of claim 11, wherein the removable cover isattached to the lower disk support plate.
 16. The transformer system ofclaim 11, further comprising a valve disposed between the electricaltransformer and the depressurization system.
 17. The depressurizationsystem of claim 11, wherein the rupture disk further comprises a scoreline network extending circumferentially around the domed portion ofrupture disk adjacent the base and spaced apart from the apex.
 18. Thedepressurization system of claim 17, wherein the score line networkcomprises one or more serrated score line segments.
 19. A transformersystem comprising: an electrical transformer having a chamber in which amagnetic core and electrical conductors are disposed in a coolant, thechamber having an outlet defined therein; a depressurization system influid communication with the outlet of the electrical transformer, thedepressurization system comprising: a first pipe section extending fromthe outlet; a second pipe section in fluid communication with the firstpipe section; and a rupture disk having a domed portion with a concaveside and convex side, the domed portion characterized by an apex and abase, the rupture disk including a retention portion surrounding thedomed portion adjacent the base, with a score line network extendingcircumferentially around the domed portion of rupture disk adjacent thebase and spaced apart from the apex, the score line network having aplurality of score line segments, wherein the rupture disk is clampedbetween a lower disk support plate and an upper disk support plate sothat the domed portion of the rupture disk extends into a bore of one ofthe disk support plates; and a rupture disk housing assembly having acontainer with an opening therein to define a cavity, a first flangeattached to the container, a second flange attached to the containerwith a through bore extending between the first flange and the secondflange and intersecting the cavity; and a removable cover enclosing theopening of the rupture disk housing, wherein the first flange connectsto the first pipe section upstream of the depressurization system andthe second flange connects to the second pipe section downstream of thedepressurization system, wherein the rupture disk is removable from therupture disk housing assembly without disconnecting either of the firstflange from the first pipe section or the second flange from the secondpipe section.
 20. The depressurization system of claim 19, wherein thescore line segments are serrated.
 21. The transformer system of claim19, further comprising a valve disposed between the electricaltransformer and the depressurization system.
 22. The transformer systemof claim 19, further comprising an elongated, substantially horizontalpipe having a first end attached to the second pipe section and a secondend to which a flame suppressor is attached.
 23. The transformer systemof claim 22, wherein the flame suppressor is oriented substantiallyhorizontally.
 24. The transformer system of claim 19, wherein theremovable cover is attached to the lower disk support plate.
 25. Thetransformer system of claim 19, wherein each score line segment isserrated and includes two spaced apart hinge score lines, with hingescore lines of adjacent score line segments being spaced apart from oneanother at the adjacent ends of the score line segments.